Photo 1 of 2: At Randolph Street I approach the “mixing zone” and position my bicycle to ride from the bike lane to the left side of the drivers waiting to turn right.

In some of my social circles where bicycling is frequently discussed (with fellow transportation planners, advocates, or just people who bike commute frequently) we talk about Chicago’s new protected bike lanes, which started appearing in 2011.

The subject of their design is brought forth: they exacerbate turning conflicts between bicyclists going straight and drivers turning right (and to a lesser extent, left). Participants in these discussions usually express appreciation for the protected bike lanes, largely because of their ability to reduce injuries overall and influence in bringing new people to bicycling, but are hard pressed to ignore this issue.

The issue is created in some instances when bicyclists are removed from sight of drivers because the bike lane is separated from the travel lanes by a vision-blocking lane of parked cars. However, the Chicago Department of Transportation has attempted to mitigate the turning issue by creating “mixing zones” where turning cars are and through-bicycles are mixed into the same, very wide lane prior to the intersection. When there is a green light, drivers typically merge into the mixing zone without much deceleration and then make the turn regardless of the bicyclist’s position.

Allowing turning cars and through-bicycles to go through these movements in the same place at the same time is a situation of incompatible demands.

Photo 2 of 2: I apparently didn’t position myself far enough to the left because the driver of this black Toyota turned right across my path.

It’s highly unclear where the bicyclist is supposed to go and how they’re supposed to maneuver themselves in the mixing zone. If the bicyclist follows the lane and then the sharrows, they will be stuck behind cars. One of the pavement markings shows a small arrow above a bicycle symbol possible indicating that bicyclists must turn here (even though a sign says bicyclists and buses don’t have to turn from the lane).

The mixing zones on Desplaines Street are the worst at this, possibly because of the street’s nature as one that moves drivers exiting the city onto streets that lead into the Kennedy Expressway. People are gunning for the highway to get home and people bicycling tend to be in the way.

Additionally, the mixing zones on Desplaines Street differ from other protected bike lane installations (like the first one on Kinzie and subsequent ones on Elston, 18th, and Milwaukee) in that they lack the green lanes that CDOT has been using to highlight where car traffic crosses bike lane traffic.

Desplaines Street has another issue that arises when the signal is red and a bicyclist and a driver are both waiting for a green light. The bicyclist is between the car and the curb. The driver then makes a right turn on red (disregard whether or not a sign control makes this illegal) across the path of the stopped bicyclist. No harm done, right? Maybe, but there are a couple possibilities where this could be dangerous: the driver makes this movement as the light turns green and the bicyclist is attempting to move straight. Or there’s the possibility that the bicyclist also wants to turn right and the driver and bicyclist do so simultaneously without accommodating what the other may be doing. Both situations could lead to the dreaded “right hook”.

The driver of this white Hyundai makes a legal right turn from a “mixing zone” to Madison Street. However, what if the bicyclist wanted to also turn right, or the driver made this as the light was turning green?

The solution to the incompatible desire for one group of roadway users to turn and for the other group to go straight is to separate their movements with traffic signals, which CDOT has done on Dearborn Street.

With these situations in mind, it’s not unexpected to see a bicyclist move through the intersection on a red light to avoid a potential incident at the intersection, the site of most bike-car crashes. CDOT has reported that the red light compliance of people bicycling on Dearborn Street – the only street with bike-only signals – “has increased from only 31 percent of cyclists stopping for reds before the lanes and bike-specific traffic signals were installed, to 81 percent afterwards”.

I don’t think there’s not a problem with protected bike lanes but their precarious design in Chicago as well as the variations within Chicago and across the United States.